Vampire romance is bad enough, but at least you can make that seem semi-plausible. Vampires may not reproduce sexually, but they inhabit bodies that used to be human, and also it makes sense for them to be attractive to humans, because being able to lure humans to their doom is necessary to their survival. Angels don't need to get humans to stick around to be eaten, and they're not actually corporeal, unless you believe Milton.
Indeed, angels as the Christian tradition describes them are not well suited to being protagonists of novels, even if you leave the romance out of it, because they are atemporal - there's a reason why the only author I can think of who more or less gets away with it is Milton, whose angels are not, strictly speaking, quite according to the tradition*. The book of Tobit has it both ways, by revealing at the end that Raphael was just simulating humanity for the purpose of helping Tobiah, which is unsatisfying from a literary point of view, but rescues the theology. Actually I think that if you want to write stories involving angels you can do it more easily in an SF context - Lewis makes a decent fist of it (there are things about the cosmic trilogy I find very problematic, but the Eldila are, I think, really quite good). Deep Space Nine's Prophets can just about be viewed as occupying more or less the same conceptual space and again, I think succeed pretty well. Like the Eldila, they're interesting because they're definitely not humans with wings pasted on, but a different kind of being altogether, and the writers are willing to try and face the challenge of writing about unincarnate, atemporal beings - even when we do get the big revelation about Sisko's origins, it's not the Tragic Doomed Angel-Human Romance, but something more unsettling and inhuman.
Of course, to be fair to the author of Daughter of Smoke and Bone, her angels are corporeal, mortal, and reproduce sexually (and have very messed up family structures). This makes a romance more plausible, I admit, though it does raise the very germane question, in what sense are these actually angels?**
You might, at this point, ask, "Why did you buy it?" The answer is (a) because I am a sucker for stories involving doors into other worlds***, and also because while I read the first chapter, I missed the one sentence prologue that would have told me what I was in for.
The sad part is that there are parts of the book I really like - the doors into other worlds are fun; her 'chimera'/ monsters (which turn out to be demons, alas) are quite charming and sinister at the same time, and I like the opening conceit of the heroine living a more or less normal art student existence, while also running dubious errands for the surprisingly likable monster who brought her up. There's also an interesting take on magic.
But I can't be bothered with angel romance; I'm not even sure if I want to finish reading it, although I rarely leave books unread, so I probably will. But unless I experience a sudden epiphanic change of heart, it will go straight to Oxfam.
* Though it's not as glaring a deviation as his Christology, which is flat-out heretical.
** They don't seem to be messengers of God, either, or at least the angelic hero hasn't got a scooby about what the purpose of his life is or why his people are locked in combat with 'the fallen'). Basically I think the problem is that the author wanted some way of doing paranormal Romeo and Juliet that didn't involve vampires vs werewolves, but really, angels?
*** CS LEWIS MADE ME DO IT!!!111!!!